Conventionally, such a writing implement has been utilized that a soft grip member is fitted at a vicinity of a tip end of its shaft tube gripped by a user in order not to slip the grip and not to pain the user's fingers while the user writes for a long time.
More specifically, the shaft tube formed in a cylindrical shape of the writing implement includes a reduced-diameter part formed by reducing the diameter of the shaft tube in the vicinity of its tip end. Further, a grip member formed in a cylindrical shape with an inner diameter corresponding to the reduced-diameter part is fitted on the diameter-reduced part of the shaft tube.
As a material for such a grip member, a soft elastic material like a rubber such as EPDM (ethylene-propylene-diene rubber) and NBR (acrylonitrile-butadiene rubber), or thermoplastic elastomer is generally used.
Moreover, silicon rubber that gives a user gel-like feel such as gel of fluent material can also be adopted as the material for the grip member.
Here, when the grip member formed of an elastic material is deformed by a griping force, it is forced to return to its original shape due to its elastic force. Therefore, the user feels bounce and does not have an excellent fit.
On the other hand, when the silicon rubber having a gel-like feeling adopted as the material for the grip member is deformed by external force, it is elastically deformed in such a plastically deforming manner that the silicon rubber gradually returns back to its original shape. Therefore, bounce due to elastic deformation hardly occurs when the user grips the grip member, and the grip member deforms in conformity with a shape of a finger tip of the user due to griping force of the user, whereby giving the user an excellent fit (e.g. Patent document 1).
Patent document 1:JP 2004-291612 A